We have been studying the specific biochemical mechanisms involved in the replication of the autonomous parvovirus, KRV in a rat nephroma cell line. The virus, isolated originally from a rat sarcoma, contains one molecule of linear, single-stranded DNA and three capsid proteins. Little information is available about replication of a single-stranded DNA virus in a eukaryotic cell or on the transcription of this DNA to make viral proteins. We have demonstrated that the virion KRV-DNA can self prime in vitro to synthesize the double-stranded replicative intermediate. In an attempt to resolve this self priming terminus, so important in DNA replication, we have sequenced the nucleotides in the 3' DNA terminus which probably also contains the in vitro origin of DNA replication.